"She was trying to describe some of the acts that are basically no-nos," said Tom Lorenz, spokesman for the Glendale Police Department. "The child began to cry and said, 'Mommy, the babysitter has been doing this to me.'"

According to Lorenz, Liu would take the kids out "on average of up to four hours" at a time, at least once a month for the past eight months.

Lorenz wasn't able to disclose where they had gone, but the "child brought it up and we were able to confirm."

The 8-year-old's mother had hired Liu to babysit the night her son told her about the alleged abuse.

"Had [the mother] not inquired the way she had done, her son would have been out with the babysitter again that night," Lorenz said. "What is it really going to hurt to ask your kids that very question or to educate them, whether it be sex, drugs, inappropriate touching … if you don't, the consequences are pretty apparent."

The family had found Liu on Sittercity.com, a website that matches families with babysitters. His account has since been terminated, according to Sittercity spokeswoman Mary Schwartz, and the company has notified "anyone who may have had contact with him about the termination."

Sittercity, like many websites that offer provider services, does background checks on member caregivers and cross- checks their identities with profiles on state sex offender registries, but according to Lorenz, Liu did not have a record of any kind.

"There's always a first time," he said.

Liu had also registered on Care.com, another website that matches sitters with families. According to the website's spokeswoman, Jo Flattery, Liu had been a member since 2008. During that time, she said, he had been in contact with "a little over 300 people" but there is no way of knowing if he had worked for any of those families, she added. His profile has now been deactivated.

Liu's attorney, Michael Shannon, did not immediately respond to an interview request from ABCNews.com.

It's still unknown if there are any other alleged victims.

"Our detectives fear the worst, but they're hoping for the best," said Lorenz.

On police forms, Liu listed his occupation as "photographer" according to Lorenz, but little else about Liu has been released by the detectives conducting the investigation.

He does, however, have a presence on social network websites.

Liu's Facebook profile picture shows Liu standing next to a boy who appears to be a teenager.

And a YouTube user with the same handle as the Facebook page, e40ish, posted "cultural commentaries" featuring Liu where he expounds on "religion in extinction" and "endangered language."

"People are insisting on the expansion of those options which have defined their spiritual and religious possibilities until now," he said in one video. "The real story here is not the potential extinction of religion but the explosion of choice which people increasingly feel is their right."

There are 64 other videos posted on YouTube by user e40ish, including videos of 14-year-old singer Greyson Chance performing at The Grove, in Los Angeles, and at the House of Blues.

Police are currently investigating whether or not Liu babysat for other families.

"We know he has conversed with well over 100 parents. Our investigation as it continues will determine if another family did hire him for services," said Lorenz.